JP2019196013A - Disposal of waste material for 3d printing - Google Patents

Abstract

To provide a method and system for disposal of waste materials in 3D printing or additive manufacturing.SOLUTION: There is provided an additive manufacturing apparatus that generates a waste ink in a process of additive manufacturing, comprising: a waste ink collection device configured to recover the waste ink from an additive manufacturing location; and a waste ink curing device configured to cure the waste ink after collection.SELECTED DRAWING: Figure 9

Description

  The present invention relates in some embodiments to a method and apparatus for waste treatment in 3D printing or additive manufacture, and more particularly to a method of waste treatment that is environmentally safe, It is not limited to it.

  3D printing, also known as add-on manufacturing, is a technology that has been developed and improved over the last 20 years and is now practical and useful for industrial applications. 3D printing builds unit objects from the bottom up by adding materials one layer at a time, thus making it possible to form unique individual parts with unmatched complex shapes.

  3D printing is performed using a special ink or resin that is jetted using a nozzle to form a layer when in liquid form, and then the layer is rolled by a roller to form a smooth shape, followed by rolling, The layer is cured using LED light that solidifies the ink.

  The roller generates a significant amount of waste, which is about 10-30% of the original jetting ink volume. Further waste ink is generated by a head maintenance procedure such as purging the head or ejecting residual ink. Liquid waste resin is considered a hazardous substance and requires proper storage and processing. Needless to say, removing about 30% of the liquid ink after use is a significant burden on the operation of the printer, and environmentally friendly processing is expensive.

  Currently, waste is collected and pumped into a disposable container that is transported to a disposal facility when the container is full. The facility disposes of waste and disposes of it appropriately.

  The purpose of this embodiment is to solve the problems of the prior art by eliminating the need for safe disposal of unused liquid resin.

  Unused liquid resin may be automatically recovered and cured. The cured ink is no longer a hazardous material and standard waste can be used. Curing may be performed during collection immediately after the generation of waste, and this embodiment may ensure that there is no significant storage of hazardous waste.

According to an aspect of some embodiments of the present invention, there is an additive manufacturing device that generates waste ink in the course of additive manufacturing,
A waste ink recovery device configured to recover waste ink from an additional manufacturing location;
A waste ink curing device configured to cure waste ink immediately after collection;
Provide equipment with

In one embodiment, the waste ink curing device comprises:
A collection cartridge for collecting liquid waste ink;
A curing energy source for curing the waste ink;
including.

  In one embodiment, the waste ink curing device further includes a switch that activates the curing energy source when the ink is evenly distributed within the cartridge.

  In one embodiment, the switch is configured to delay the operation of the curing energy source in anticipation of the time for the waste ink droplets that drip into the cartridge to merge.

In one embodiment, the waste ink collection device comprises:
A reservoir for collecting waste ink from rollers or from printhead maintenance operations;
A piping system for distributing waste ink to drip points evenly distributed throughout the collection cartridge;
including.

  In one embodiment, the waste ink collection cartridge includes an array of distributed drip points for evenly distributing the waste ink throughout the waste ink collection cartridge.

  In one embodiment, the curing energy source is arranged to radiate energy evenly across the cartridge.

  In one embodiment, the curing energy source comprises a bank or strip of light emitting diodes, typically UV light emitting diodes.

  In one embodiment, the curing energy source is disposed longitudinally along one side of the cartridge.

  In one embodiment, the drip point includes a shield against curing energy from a curing energy source to prevent the waste ink from being cured before dripping from the drip point.

  In one embodiment, the shield includes a hood that surrounds each drip point.

  One embodiment may include a discharge shovel that directs the drip under each drip point.

  In one embodiment, the curing energy source includes three diode banks, the first bank is disposed longitudinally on the first side of the cartridge, the second bank is disposed longitudinally on the second side of the cartridge, The third bank is disposed longitudinally over the exit point, and the third bank is configured to operate once to cure the undropped ink immediately after the cartridge reaches full condition.

  In one embodiment, the cartridge includes a level detector that detects the current level of waste ink in the cartridge, thereby determining when the cartridge is full.

  In one embodiment, the liquid level detector includes a prism having a refractive index selected to produce total internal reflection except when surrounded by waste ink.

  In one embodiment, the curing energy source includes first and second bank diodes, each oriented at an oblique angle with respect to the cartridge floor.

According to a second aspect of the invention,
Delivering ink to an additional manufacturing location;
Collecting waste ink from the additional manufacturing location;
Curing the waste ink immediately after collection;
A method for managing waste ink during additive manufacturing is provided.

This method
Monitoring the waste ink flow rate;
Activating curing according to the waste ink flow rate;
May be included.

In one embodiment, the waste ink curing step comprises:
Collecting liquid waste ink; and
Curing the waste ink with curing energy;
including.

  This method may activate the curing energy source after the ink is evenly distributed in the cartridge.

  The method may include delaying the operation of the curing energy source in anticipation of the time for waste ink droplets to drip into the cartridge to merge.

In one embodiment, the waste ink recovery step comprises:
Collecting the waste ink from the rollers or from the printhead maintenance work;
Distributing the waste ink evenly throughout the collection cartridge;
including.

  The method may include radiating curing energy evenly across the cartridge.

This method
Detecting when the cartridge is full,
Irradiating the drip tube of the cartridge to cure the undripped ink; and
May be included.

  According to a third aspect of the present invention, there is provided a cartridge for receiving waste ink from an additive manufacturing apparatus, the cartridge including a distribution head, a curing source, and a container, wherein the distribution head is disposed on the inlet tube and the entire cartridge. And an array of distributed drip points, each drip point being surrounded by a shield to protect against direct irradiation from the curing source, the curing source having a plurality of radiation locations disposed around the container. A cartridge comprising the cartridge is provided.

  The drip point may include a sharp end for droplet formation.

  The cartridge may include a drip guide shovel under each drip point and within the shield.

  The cartridge may include a second curing source in the dispensing head for curing ink remaining in the dispensing head when the cartridge is full.

  The cartridge may include a liquid level detector that detects cartridge filling. The liquid level detector may use an LED, a simple reflection with the detector, or a prism as described herein.

According to a fourth aspect of the present invention, there is provided a method for controlling curing in an additive manufacturing device that generates waste ink in the course of additive manufacturing,
The equipment is
A waste ink recovery device configured to recover waste ink from an additional manufacturing location;
A waste ink curing device configured to cure the waste ink immediately after collection;
With
Estimating the flow rate of resin to the waste ink collection device;
Calculating the timing and amount of resin when the resin arrives at the waste ink recovery device using the estimation;
Activating the curing at a timing and application amount suitable for the calculated amount;
A method is provided.

  Unless defined otherwise, all technical and / or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, exemplary methods and / or materials are described below. In case of conflict, the patent specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.

  Several embodiments of the invention are merely illustrated herein and described with reference to the accompanying drawings. With particular reference to the drawings in particular, it is emphasized that the details shown are only intended to illustrate the embodiments of the invention by way of example. In this regard, the manner in which embodiments of the present invention are implemented will become apparent to those skilled in the art from the description given with reference to the drawings.

FIG. 1A is a schematic diagram of an additive manufacturing system according to some embodiments of the present invention. 1B-1C are schematic diagrams of an additive manufacturing system according to some embodiments of the present invention. FIG. 1D is a schematic diagram of an additive manufacturing system according to some embodiments of the present invention.

2A-2C are schematic views of a print head according to some embodiments of the present invention.

3A-3F are schematic diagrams that demonstrate coordinate transformations according to some embodiments of the present invention.

FIG. 4 is a simplified diagram showing an additional manufacturing apparatus with waste collection according to an embodiment of the present invention.

FIG. 5 is a simplified diagram illustrating a path of waste ink or waste resin from a printing position to a collection cartridge according to an embodiment of the present invention. FIG. 6 is a simplified diagram showing a head portion of a cartridge assembly according to an embodiment of the present invention.

FIGS. 7-8 are photographs of collection cartridges according to one embodiment of the present invention, showing waste ink at two different coalescence stages.

FIG. 9 shows a side cutaway view of the waste ink collection cartridge according to one embodiment of the present invention, and is a simplified diagram showing the position of the curing LED.

FIG. 10 shows the structure and position of the drip point in the shower head of the recovery cartridge according to the embodiment of the present invention.

FIG. 11 is a simplified diagram showing a cutaway view of a drip exit point in a shower head according to an embodiment of the present invention.

12A-12C are three cutaway views of a waste ink collection cartridge according to one embodiment of the present invention.

13A-13B are two cross-sectional side views of a liquid level detector for a recovery cartridge according to one embodiment of the present invention.

FIG. 14 is an alternative embodiment of a liquid level detector for a recovery cartridge according to the present invention.

FIG. 15 is a flowchart showing the operation of a waste ink recovery and curing process according to an embodiment of the present invention.

FIG. 16 is a simplified flow diagram illustrating monitoring of waste ink flow rate and control of cure speed or application amount using the results according to one embodiment of the present invention.

FIG. 17 is a photograph showing various stages of resin or ink accumulation in a collection cartridge during operation of the present invention.

FIG. 18 is a photograph showing the layered structure of the cured waste resin.

FIG. 19 is a photograph showing the accumulation of sarcophagus.

FIG. 20 is a photograph showing the uncured pockets of the liquid resin within the generally cured mass.

21A to 21C are photographs showing how liquid resin pockets are formed in the shadow resulting from the accumulation of sarcophagus.

FIG. 22 is a photograph showing the location of an LED according to one embodiment of the present invention and how the curing light covers the interior of the cartridge by illumination from at least two points using a triangle. .

FIG. 23 is a simplified diagram illustrating a waste treatment system for a 3D printer according to a further embodiment of the present invention.

FIG. 24 is an exploded view of the system of FIG.

FIG. 25 is a simplified diagram showing the waste guidance components of the system of FIG.

FIG. 26A shows the showerhead components of the system of FIG. FIG. 26B is a detail of a portion of the component of FIG. 26A.

27-28 are different perspective views of the structure within the waste guide component of FIG.

29 is a different perspective view of the structure within the waste guidance component of FIG.

FIG. 30 is a simplified side view of the waste guidance component of FIG.

31 is a simplified side view of the waste guide component of FIG. 25 attached to the showerhead component of FIG. 26A.

32-34 is a simplified diagram illustrating a protective structure for protecting the drip opening of the system of FIG. 23 from accidental curing.

FIG. 35 shows the formation of icicles from drip openings with poor protection.

FIG. 36 shows the interrelationship of LEDs and drip holes to ensure even cure in accordance with an embodiment of the present invention.

FIG. 37 illustrates a virtual waste pipeline model for predicting resin flow rate to calculate the exact timing and application amount of cure in accordance with one embodiment of the present invention.

  The present invention, in some embodiments thereof, relates to the treatment of waste ink or waste resin during additive manufacturing, and more particularly, but not exclusively, to a method that allows standard waste treatment to be used safely. .

  Unused resin is a hazardous substance and must be treated using special waste treatment techniques, which are generally the responsibility of the resin supplier. The 3D printing process generates a significant amount of waste, usually about 10-30% of the amount ejected by the head. Additional waste is also generated by head maintenance procedures such as purging and dispensing.

  While liquid waste resin is considered harmful, cured resin is not harmful and can be disposed of in a regular trash can. Therefore, in the present embodiment, the waste resin is cured in a generated state. When the waste resin cartridge is full, the user simply throws the cartridge into the trash and replaces the cartridge with a new one.

  Before describing at least one embodiment of the present invention in detail, the present invention is applied in its application to the components and / or methods shown in the following description and / or illustrated in the drawings and / or examples. It should be understood that the present invention is not necessarily limited to the details of assembly and construction. The invention is capable of other embodiments or of being practiced or carried out in various ways.

  The method and system of this embodiment produce a three-dimensional object layer by layer based on computer object data by forming a plurality of layers in a configuration pattern corresponding to the shape of the object. Computer object data includes standard tessellation language (STL) or stereolithography contour (SLC) format, virtual reality modeling language (VRML), additive manufacturing file (AMF) format, drawing interchange format (DXF), polygon file Any known format can be used, including but not limited to format (PLY) or any other format suitable for computer aided design (CAD).

  As used herein, the term “object” refers to an entire object or a portion thereof.

  Each layer is formed by additive manufacturing equipment that scans the two-dimensional surface and patterns it. During the scan, the instrument visits a plurality of target positions on the two-dimensional layer or surface, and for each target position or group of target positions, whether the target position or group of target positions should be occupied by the building material, And what type of building material should be delivered to it. The determination is made according to the computer image of the surface.

  In a preferred embodiment of the present invention, the AM includes three-dimensional printing, more preferably three-dimensional ink jet printing. In these embodiments, the build material is discharged from a discharge head having a set of nozzles, depositing the build material in layers on a support structure. The AM device thus dispenses the build material to the target position to be occupied and leaves the other target positions empty. The instrument typically includes a plurality of ejection heads, each ejection head can be configured to eject a different build material. Thus, different building materials can occupy different target positions. The types of construction materials can be mainly classified into two categories: model materials and support materials. The support material serves as a support matrix or support structure to support an object or part of an object during the fabrication process and / or to provide a hollow object or porous object for other purposes, for example. The support structure may further include model material elements, for example, to increase support strength.

  Model materials are generally compositions formulated for additive manufacturing and can form three-dimensional objects on their own, i.e., without the need to mix or combine with other materials.

  The final three-dimensional object is made from a model material, or a combination of model materials, or a combination of model material and support material or modifications thereof (eg after curing). All of these operations are well known to those skilled in the art of solid freeform.

  In some exemplary embodiments of the present invention, the object is manufactured by dispensing two or more different model materials, each material being dispensed from a different dispensing head of the AM. The material is optionally and preferably deposited in layers during the same pass of the print head. The materials and material combinations in the layers are selected according to the desired properties of the object. A representative and non-limiting example of a system 110 suitable for AM of an object 112, according to some embodiments of the present invention, is shown in FIG. 1A. The system 110 includes an additional manufacturing device 114 having a discharge unit 16 including a plurality of discharge heads. Each head preferably includes an array of one or more nozzles 122 through which the liquid build material 124 is dispensed, as shown in FIGS. 2A-2C described below.

  Device 114 is preferably a three-dimensional printing device, but is not essential. In that case, the ejection head is a print head and the build material is ejected via inkjet technology. Depending on the application, additional manufacturing equipment may not need to employ 3D printing technology, so this is not necessarily true. Representative examples of additive manufacturing equipment envisioned in accordance with various exemplary embodiments of the present invention include, but are not limited to, hot melt additive manufacturing equipment and hot melt material deposition equipment.

  Each dispensing head is optionally and preferably supplied via a build material reservoir, which may optionally include a temperature control unit (eg, a temperature sensor and / or a heating device) and a material level sensor. In order to eject the build material, a voltage signal is applied to the ejection head so that droplets of material are selectively deposited via the ejection head nozzle, as in the case of piezoelectric inkjet printing technology, for example. The ejection rate of each head depends on the number of nozzles, the type of nozzle, and the signal rate (frequency) of the applied voltage. Such discharge heads are known to those skilled in the art of three-dimensional free-formation.

  The total number of discharge nozzles or nozzle arrays is designed so that half of the discharge nozzles discharge the support material, and half of the discharge nozzles are designed to discharge the model material, that is, the number of nozzles that eject the model material is It is preferable to select the number of nozzles for ejecting the support material, but it is not essential. In the exemplary embodiment of FIG. 1A, four ejection heads 16a, 16b, 16c, and 16d are shown. Each of the heads 16a, 16b, 16c, and 16d has a nozzle array. In this embodiment, the heads 16a and 16b can be designed for model material and the heads 16c and 16d can be designed for support material. Thus, the head 16a can discharge the first model material, the head 16b can discharge the second model material, and both the heads 16c and 16d can discharge the support material. In an alternative embodiment, for example, the heads 16c and 16d may be combined into a single head having two nozzle arrays for discharging support material.

  Nevertheless, it is not intended to limit the scope of the invention and it is understood that the number of model material ejection heads (model heads) and the number of support material ejection heads (support heads) may vary. I want to be.

  In general, the number of model heads, the number of support heads, and the number of nozzles in each head or head array are determined by a predetermined ratio α between the maximum discharge rate of the support material and the maximum discharge rate of the model material. Is selected to yield. The value of the predetermined ratio α is preferably selected to ensure that the height of the model material in each layer to be formed is equal to the height of the support material. Typical values for α are about 0.6 to about 1.5.

  As used herein, the term “about” refers to ± 10%.

  For example, when α = 1, when all model heads and support heads are operating, the total discharge rate of the support material is substantially the same as the total discharge rate of the model material.

  In the preferred embodiment, there are M model heads each having m arrays of p nozzles and S support heads each having s arrays of q nozzles, so that M × m × p = S × s. Xq. Each of the M × m model array and the S × s support array can be manufactured as a separate physical unit, which can be assembled into or disassembled from the array group. In this embodiment, each such array optionally and preferably includes its own temperature control unit and material level sensor and receives individually controlled voltages for its operation.

  The instrument 114 can further include a curing device 324, which can include any device configured to emit light, heat, etc. that cures the deposited material. For example, the curing device 324 can include one or more radiation sources, which can be, for example, ultraviolet or visible light or infrared lamps, or other electromagnetic radiation sources, or electron beam sources, depending on the model material used. be able to. In some embodiments of the present invention, the curing device 324 serves to cure or solidify the model material.

  The discharge head and radiation source are preferably mounted on a frame or block 128 that preferably operates to reciprocate on a tray 360 that serves as a work surface. In some embodiments of the invention, the radiation source is attached to the block such that the radiation source follows the ejection head to at least partially cure or solidify the material just ejected by the ejection head. The tray 360 is arranged horizontally. In accordance with common conventions, the XYZ Cartesian coordinate system is selected so that the XY plane is parallel to the tray 360. The tray 360 is preferably configured to move vertically (along the Z direction), usually downward. In various exemplary embodiments of the present invention, the instrument 114 further comprises one or more leveling devices 132, such as rollers 326. Leveling device 326 serves to correct, level, and / or establish the thickness of the newly formed layer before the next layer is formed thereon. The leveling device 326 preferably includes a waste collection device 136 for collecting excess material generated during leveling. Waste collection device 136 may include any mechanism for delivering material to a waste tank or waste cartridge. The waste collection will be described in detail later.

  During use, the ejection head of unit 16 moves in a scanning direction, referred to herein as the X direction, to selectively eject the build material into a predetermined configuration as they pass over tray 360. The construction material typically includes one or more support materials and one or more model materials. Following the passage of the discharge head of the unit 16, the model material is cured by the radiation source 126. During the reverse pass of the head back to the starting point of the head for the just deposited layer, an additional discharge of build material may be performed according to a predetermined configuration. During the forward or reverse passage of the discharge head, the layer thus formed is corrected by a leveling device 326 that preferably follows the path of the discharge head during the forward and / or reverse movement of the leveling device. As the discharge heads return to their starting points along the X direction, the discharge heads move to another position along the indexing direction, referred to herein as the Y direction, and reciprocate along the X direction to move the same layer. You can continue building. Alternatively, the ejection head may move in the Y direction during forward and reverse movement or after two or more forward-reverse movements. The series of scans performed by the ejection head to complete a single layer is referred to herein as a single scan cycle.

  When the layer is completed, the tray 360 is lowered in the Z direction to a predetermined Z level, depending on the desired thickness of the next layer to be printed. This procedure is repeated so that the three-dimensional object 112 is formed layer by layer.

  In another embodiment, the tray 360 may be displaced in the Z direction during forward and reverse passage of the discharge heads of the unit 16 within the layer. Such Z displacement is performed to bring the leveling device in contact with the surface in one direction and to prevent contact in the other direction.

  System 110 optionally and preferably comprises a building material supply system 330 that includes a building material container or cartridge and supplies a plurality of building materials to manufacturing equipment 114.

  The control unit 340 also controls the manufacturing equipment 114 and optionally and preferably also the supply system 330. Control unit 340 typically includes electronic circuitry configured to perform control operations. The control unit 340 communicates with a data processor 154 that transmits digital data regarding production instructions based on a CAD configuration represented in a computer readable medium in the form of computer object data, eg, standard tessellation language (STL) format. It is preferable to do. Typically, the control unit 340 controls the voltage applied to each ejection head or nozzle array and the temperature of the construction material of each print head.

  Once the manufacturing data is loaded into the control unit 340, the control unit can operate without user intervention. In some embodiments, the control unit 340 receives additional input from the operator using, for example, the data processor 154 or the user interface 116 that communicates with the unit 340. The user interface 116 may be any type known in the art, such as, but not limited to, a keyboard, a touch screen, and the like. For example, the control unit 340 can receive as an additional input one or more building material types and / or attributes such as color, characteristic distortion, and / or transition temperature, viscosity, electrical properties, magnetic properties, and the like. However, it is not limited to them. Other attributes and attribute groups are also possible.

  Another representative and non-limiting example of a system 10 suitable for object AM according to some embodiments of the present invention is shown in FIGS. 1B-1D. 1B-1D show a top view (FIG. 1B), a side view (FIG. 1C), and an isometric view (FIG. 1D) of the system 10.

  In this embodiment, the system 10 includes a tray 12 and a plurality of inkjet print heads 16 each having a plurality of separate nozzles. The tray 12 can have a disk shape or can be annular. Non-circular shapes are also conceivable on the premise that they can be rotated about a vertical axis.

  The tray 12 and the head 16 are optionally and preferably mounted for relative rotational movement between the tray 12 and the head 16. This is because (i) the tray 16 rotates about the vertical axis 14 with respect to the head 16, and (ii) the head 16 rotates about the vertical axis 14 with respect to the tray 12. Or (iii) by configuring both the tray 12 and the head 16 to rotate about the vertical axis 14 but at different rotational speeds (eg, rotating in opposite directions). can do. In the following embodiment, the configuration (i) in which the tray is a rotating tray configured to rotate around the vertical axis 14 with respect to the head 16 will be described with particular emphasis. It should be understood that and (iii) are also contemplated. Any of the embodiments described herein can be adjusted to be applicable to either configurations (ii) and (iii), and how such adjustments are made given the details described in this document. Will be understood by those skilled in the art.

  In the following description, a direction parallel to the tray 12 and outward from the axis 14 is referred to as a radial direction r, and a direction parallel to the tray 12 and perpendicular to the radial direction r is referred to herein as an azimuth direction φ and is perpendicular to the tray 12. This direction is referred to herein as the vertical direction z.

  As used herein, the term “radial position” refers to a position on or above the tray 12 that is a specific distance from the axis 14. When the term is used in connection with a print head, the term refers to the position of the head at a specific distance from the axis 14. When this term is used in reference to a point on the tray 12, this term means any point belonging to the locus of a circle that draws a circle whose radius is a specific distance from the axis 14 and whose center is at the axis 14. Corresponding to

  As used herein, the term “azimuth position” refers to a position on or above the tray 12 at a specific azimuth with respect to a predetermined reference point. Therefore, the radial position refers to an arbitrary point belonging to the locus of a point that draws a straight line that forms a specific azimuth with respect to the reference point.

  As used herein, the term “vertical position” refers to the position of the entire plane that intersects the vertical axis 14 at a particular point.

  The tray 12 serves as a support structure for three-dimensional printing. The working area where one or more objects are printed is typically smaller than the total area of the tray 12, but this is not necessarily so. In some embodiments of the invention, the work area is annular. The work area is indicated by 26. In some embodiments of the invention, the tray 12 rotates continuously in the same direction throughout the formation of the object, and in some embodiments of the invention, the tray is at least once (eg, Reverse direction of rotation (to vibrate). The tray 12 is optionally and preferably removable. Removal of the tray 12 can be done for maintenance of the system 10 or, if desired, to replace the tray before printing a new object. In some embodiments of the invention, the system 10 is provided with one or more different replacement trays (eg, a kit of replacement trays), where two or more trays are different types of objects (eg, different weights), different operations. Designed for modes (eg different rotational speeds) etc. The tray 12 can be replaced manually or automatically as desired. If automatic replacement is employed, the system 10 includes a tray changer 36 configured to remove the tray 12 from its position under the head 16 and replace it with a replacement tray (not shown). . In the representative view of FIG. 1B, the tray changer 36 is shown as a drive 38 having a movable arm 40 configured to pull the tray 12, although other types of tray changers are also contemplated.

  An exemplary embodiment of the print head 16 is shown in FIGS. 2A-2C. These embodiments can be employed in any of the AM systems described above, including but not limited to system 110 and system 10.

  2A-2B show a print head 16 having one (FIG. 2A) and two (FIG. 2B) nozzle arrays 22. The nozzles in the array are preferably arranged in a line along a straight line. In embodiments where a particular printhead has more than one linear nozzle array, the nozzle arrays can optionally and preferably be parallel to each other.

  If a system similar to system 110 is used, all print heads 16 are optionally and preferably oriented along the index direction with their positions along the scan direction offset from one another.

When a system similar to system 10 is used, all print heads 16 are optionally and preferably offset in their azimuthal positions and oriented radially (parallel to the radial direction). Thus, in these embodiments, the nozzle arrays of the different print heads are not parallel to each other, but rather angled with respect to each other, the angle being approximately equal to the azimuthal misalignment between the respective heads. For example, one head can be oriented radially and placed at azimuthal position φ ₁ , and another head can be oriented radially and placed at azimuthal position φ ₂ . In this example, the azimuthal misalignment between the two heads is φ ₁ -φ ₂ , and the angle between the linear nozzle arrays of the two heads is also φ ₁ -φ ₂ .

  In some embodiments, two or more print heads can be assembled into a block of print heads. In that case, the print heads of that block are generally parallel to each other. A block including several inkjet print heads 16a, 16b, 16c is shown in FIG. 2C.

  In some embodiments, the system 10 includes a support structure 30 that is located below the head 16 such that the tray 12 is between the support structure 30 and the head 16. The support structure 30 serves to prevent or reduce vibration of the tray 12 that may occur while the inkjet print head 16 is in operation. In a configuration in which the print head 16 rotates about the axis 14, it is preferable that the support structure 30 also rotates so that the support structure 30 is always directly below the head 16 (between the head 16 and the tray 12 together with the tray 12).

  The tray 12 and / or print head 16 optionally and preferably move in parallel with the vertical axis 14 along the vertical direction z such that the vertical distance between the tray 12 and the print head 16 varies. Configured. In a configuration in which the vertical distance varies by moving the tray 12 along the vertical direction, it is preferable that the support structure 30 also move in the vertical direction together with the tray 12. In a configuration where the vertical position of the tray 12 remains fixed and the vertical distance varies along the vertical direction by the head 16, the support structure 30 is also maintained in a fixed vertical position.

  Vertical movement can be established by the vertical drive 28. When a layer is completed, the vertical distance between the tray 12 and the head 16 can be increased by a predetermined vertical spacing (eg, relative to the head 16) depending on the desired thickness of the next printed layer. The tray 12 is lowered). This procedure is repeated so that the three-dimensional object 112 is formed layer by layer.

  The orientation of the inkjet print head 16, and optionally and preferably also the orientation of one or more other components of the system 10, such as the direction of movement of the tray 12, is also controlled by the controller 20. The controller may have an electronic circuit and a non-volatile storage medium readable by the circuit, the storage medium being a program instruction that, when read by the circuit, causes the circuit to perform control operations as described in further detail below. Is stored.

  The controller 20 may also include, for example, standard tessellation language (STL) or stereolithography contour (SLC) format, virtual reality modeling language (VRML), additive manufacturing file (AMF) format, drawing interchange format (DXF), polygon file format. (PLY), or any other format of computer object data suitable for computer-aided design (CAD), can also communicate with a host computer 24 that transmits digital data regarding production instructions. The object data format is generally constructed according to a Cartesian coordinate system. In such a case, the computer 24 preferably executes a procedure for converting the coordinates of each slice in the computer object data from the Cartesian coordinate system to the polar coordinate system. The computer 24 optionally and preferably transmits production instructions in the transformed coordinate system. Alternatively, the computer 24 can send the production instructions in the original coordinate system provided by the computer object data, in which case the coordinate transformation is performed by the circuitry of the controller 20.

  The transformation of coordinates enables three-dimensional printing on the rotating tray. In conventional three-dimensional printing, the print head reciprocates along a straight line on a stationary tray. In such a conventional system, the printing resolution is the same at any point on the tray, assuming that the ejection rate of the head is uniform. Unlike conventional three-dimensional printing, not all nozzles at the head point cover the same distance in the entire tray 12 at the same time. The coordinate transformation is optionally and preferably performed to ensure an equal amount of excess material at different radial locations. Representative examples of coordinate transformations according to some embodiments of the present invention are presented in FIGS. 3A-3F showing three slices of an object (each slice corresponding to a production order for a different layer of the object). . 3A, 3C, and 3E show the slices in a Cartesian coordinate system, and FIGS. 3B, 3D, and 3F show the same slices after the coordinate transformation procedure has been applied to each slice.

  Typically, the controller 20 controls the voltage applied to each component of the system 10 based on manufacturing instructions and based on stored program instructions described below.

  Typically, the controller 20 controls the print head 16 to eject build material droplets in layers to print a three-dimensional object on the tray 12 as the tray 12 rotates.

  The system 10 optionally and preferably comprises one or more radiation sources 18 depending on the model material used, for example ultraviolet or visible light or infrared lamps, or other electromagnetic radiation sources, or electronic It can be a beam source. Radiation sources can include any type of radiation emitting element including, but not limited to, light emitting diodes (LEDs), digital light processing (DLP) systems, resistive lamps, and the like. The radiation source 18 serves to cure or solidify the model material. In various exemplary embodiments of the present invention, the operation of the radiation source 18 is controlled by the controller 20, which can activate and deactivate the radiation source 18 and optionally is generated by the radiation source 18. The amount of radiation emitted can also be controlled.

  In some embodiments of the present invention, the system 10 further comprises one or more leveling devices 32 that can be manufactured as rollers or blades. Leveling device 32 serves to straighten the newly formed layer before the next layer is formed thereon. In some embodiments, the leveling device 32 has the shape of a conical roller and is arranged so that its axis of symmetry 34 is inclined with respect to the surface of the tray 12 and that surface is parallel to the surface of the tray. . This embodiment is shown in a side view of the system 10 (FIG. 1C).

  The conical roller can have the shape of a cone or a truncated cone.

The opening angle of the conical roller is preferably selected so that the ratio between the radius of the cone at any position along its axis 34 and the distance between that position and the axis 14 is constant. While the roller rotates, every point p on the surface of the roller has a linear velocity proportional to (eg, the same as) the linear velocity of the tray located vertically below point p, so this embodiment is a roller 32 makes it possible to level the layers efficiently. In some embodiments, the roller has the shape of a truncated cone having a height h, a radius R _{1 at} a distance closest to the axis 14 and a radius R ₂ at a distance farthest from the axis 14. Where parameters h, R ₁ and R ₂ satisfy the relationship R ₁ / R ₂ = (R−h) / h, where R is the farthest distance of the roller from axis 14 (eg, R is The radius of the tray 12).

  The operation of the leveling device 32 is optionally and preferably controlled by the controller 20. The controller can activate and deactivate the leveling device 32 and, optionally, its position along the vertical direction (parallel to the axis 14) and / or the radial direction (parallel to the tray 12) Its position along the direction towards or away from the axis 14 can also be controlled.

  In some embodiments of the invention, the print head 16 is configured to reciprocate relative to the tray along the radial direction r. These embodiments are useful when the length of the nozzle array 22 of the head 16 is shorter than the width along the radial direction of the work area 26 on the tray 12. Movement of the head 16 along the radial direction is optionally and preferably controlled by the controller 20.

  Some embodiments contemplate making an object by ejecting different materials from different ejection heads. These embodiments provide, inter alia, the ability to select a material from a given number of materials and define the desired combination of selected materials and their properties. According to this embodiment, to occupy different three-dimensional spatial positions by different materials, or to occupy substantially the same or adjacent three-dimensional positions by two or more different materials, The spatial location of the deposition of each material in the layer is defined, allowing a post-deposition spatial combination of materials in the layer, thereby allowing the composite material to be formed at the respective location (s) .

  Any post-deposition combination or mixing of model materials is contemplated. For example, after a particular material has been dispensed, it can maintain its original properties. However, when discharged at the same position or in the vicinity of another model material or another discharge material, a composite material having a property different from that of the discharged material is formed.

  Thus, this embodiment allows for the deposition of a wide range of material combinations, and an object in which different parts of an object can be composed of a combination of different materials, depending on the properties desired to characterize each part of the object. Making it possible.

  Further details of the principles and operation of an AM system suitable for this embodiment can be found in US Pat. No. 9031680, the contents of which are hereby incorporated by reference.

  Reference is now made to FIG. 4, which is a simplified diagram illustrating the waste ink processing subsystem of the additive manufacturing device according to the present embodiment. As described above with respect to FIG. 1A, additive manufacturing equipment 114 further includes one or more leveling devices, such as rollers 326. Leveling device 326 serves to correct, level, and / or establish the thickness of the newly formed layer before the next layer is formed thereon. The leveling device 326 preferably includes a waste collection device 136 for collecting excess resin material generated during leveling. The waste collection device 136 may include any mechanism that delivers material to a waste tank or waste cartridge 400. The waste ink curing device 402, which may be contained within the cartridge 400, is an energy source such as a light emitting diode or one or more light emitting diode banks for curing the waste material or waste ink 404 after being collected in the cartridge 400. including.

  Referring now to FIG. 5, it shows the waste ink collection device 136 in more detail. The apparatus includes a reservoir 410 that is connected to a roller 326 that may have an internal pump and that collects waste ink from the roller 326. The reservoir can further collect waste ink from printhead maintenance operations such as periodic purging of the printhead. The piping system 412 generally collects ink from the reservoir 410 by discharging waste ink from the reservoir to the cartridge 400 or the waste outlet pipe 414 using gravity. A dispensing head 416 having a showerhead configuration dispenses waste ink from the showerhead inlet 418 via the wicking channel to drip points 420 that are evenly distributed throughout the area of the collection cartridge 400. As will be described in detail later, the idea is to uniformly discharge the waste ink over the entire collecting surface of the cartridge.

  Reference is now made to FIG. 6, which is a schematic top view of the dispensing head 416 showerhead configuration. Each of the four inlets 418 from the waste tube 414 leads to a series of wicking channels 422 and then to eleven drip points or drip guide outlets 420. The idea of the drip point is to distribute the waste outlet evenly through the cartridge. The drip points are arranged as a distributed array for even distribution of waste ink throughout the floor of the waste collection cartridge.

  Referring now to FIGS. 7 and 8, they show successive stages in which the waste ink 404 is distributed throughout the floor of the cartridge 400. In FIG. 7, the distinguishable droplets are clear, but in FIG. 8, more ink arrives and the droplets coalesce. In this embodiment, the droplets are given time to coalesce before performing curing. That is, the curing energy source is activated only after a time period has elapsed for ink to be evenly distributed within the cartridge. The operation of the curing device may be set according to the flow rate of waste ink, for example. The higher the flow rate, the faster or more often the curing is performed. If the droplets fail to coalesce before performing curing, they can lead to the formation of sarcophagus, as described below.

  Reference is now made to FIG. 9, which is a simplified diagram of a cartridge 400 showing a source of curing energy as a mounting bank for ultraviolet light emitting diodes (LEDs). The bank is installed so as to uniformly irradiate the entire waste ink in the cartridge so that there is no shadow that the ink is completely cured and the liquid pool remains. In the present embodiment, three banks are provided. The first bank 430 is arranged in the length direction toward one side along the cartridge 400. The second bank is difficult to understand because of the presence of the shower head, but is arranged in the longitudinal direction on the second side of the cartridge that hits the opposite side of the bank 430. Both banks are installed at an oblique angle, and the third bank 432 is disposed in the lengthwise direction on the dispensing head above the exit point. The third bank 432 performed a curing operation when the cartridge 400 was full and remained in the dispensing head 416 to ensure that no harmful liquid resin remained anywhere in the cartridge during processing. Ink and undripped ink are cured.

  Reference is now made to FIG. 10, which is a simplified diagram showing a shield 440 disposed around each drip point 420 at the bottom of the dispensing head 416. A shield is provided to protect the drip point from the curing energy from the LED. Otherwise, ink cured at the drip point may block the drip point or lead to the formation of icicles as will be described in more detail later. Shields protect against direct irradiation and may also protect against irradiation from reflections from many directions. Although linear specular reflection from the waste ink surface to the drip point cannot be prevented, the total energy of such reflection is not sufficient to cause effective curing. That is, direct vertical light is minimal and is caused only by specular reflection from the ink at the bottom of the cartridge. As described above, the LED bank is directed to the floor at an oblique angle, thus preventing any direct reflection reaching the drip exit point.

  The shield can take the form of a hood or a cylindrical extension that extends around and surrounds each drip point. FIG. 11 shows a cutaway view of wicking channel 422, drip point 420, and shield 440.

  Referring now to FIGS. 12A, 12B, and 12C, which are a schematic longitudinal cross-sectional view of the cartridge 400, a schematic cross-sectional view of the cartridge, and a schematic bottom view of the shield array, respectively. FIG. 12A shows a showerhead or drip array 416 made from opaque plastic and a cartridge body wall 460 that may be made from clear plastic. The shield 440 is made of an opaque plastic. In FIG. 12B, it can be seen that the drip point 420 is actually the pointed end where the drip is formed and grows. A shovel 450 may be provided under each drip point in the shield to guide the drip. The drip falls onto the shovel and then exits through a larger opening that is less prone to clogging by stray UV light. In FIG. 12C, the drip points are shown with surrounding shielding and a shovel under each drip point.

  The shape of the drip guide is designed to prevent icicle stone formation at the drip point. Therefore, if the drip point is exposed, icicle stones may be formed from the drip guide. The drip guide design that shields the droplet from UV exposure does not exhibit this behavior until the droplet falls from the drip guide.

  Reference is now made to FIGS. 13A and 13B, which are schematic side views of a liquid level detector 470 that detects whether the cartridge 400 is full. The level detector 470 includes an emitter 472 and a detector 474 that are separated by an opaque spacer 476 and disposed outside the transparent cartridge wall 460. In the example shown in FIG. 13A, there are three such level sensors, and in FIG. 13B, the top image shows that light from the emitter does not reflect back to the detector in the absence of waste. In the bottom image, the waste material reflects the beam from the emitter so that it is detected by the detector, thus the cartridge can determine how much it has been filled and when it needs to be replaced. it can.

  A full cartridge is detected by a liquid level detector 470 at the rear of the unit.

  When it detects that the cartridge is full, printing is interrupted and the remaining waste flows into the cartridge. The final pulse of UV light is provided by LED strips 430 attached to the sides to cure the last waste in the main chamber of the cartridge. A third LED strip 432 (see FIG. 9) located on top of the shower head assembly then cures any material remaining in the wicking channel.

  The cartridge can be safely removed and disposed of by the user, and printing is resumed after a new waste cartridge is installed.

  Reference is now made to FIG. 14, which shows a variation of the liquid level detector 470 in which a prism 480 is molded in a transparent cartridge wall 460. The prism is designed to have a refractive index that causes total internal reflection when the cartridge is empty, but cannot reflect when the cartridge is full. An advantage of the prism embodiment over FIGS. 13A and 13B is that light is detected in the default position.

  Reference is now made to FIG. 15, which shows a method for managing waste ink during additive manufacturing. Manufacturing is performed (490), and the waste ink is removed and collected (492). After collection, the waste ink is cured (494) and then removed as a solid mass for disposal (496).

  Reference is now made to FIG. 16, which is a simplified flow diagram illustrating a cure control method according to one embodiment of the present invention. Waste flow is monitored or inferred (500), and curing is performed at longer intervals for lower flow rates and at shorter intervals for higher flow rates. In addition, the curing energy source can be limited to operate when sufficient time is allowed for the ink droplets to be evenly distributed, i.e., sufficient time for the droplets to grow and melt.

  The formation of sarcophagus is prevented by matching the timing and the applied amount, which means the amount of curing, to the flow rate. If the amount applied is too high, there will be no time for the resin to diffuse before curing, so sarcophagus is formed. On the other hand, if the amount applied is too low, a reservoir can be formed. If the reservoir is too deep, UV can cure the layer on top of the reservoir and confine the liquid resin below. When this happens, the trapped liquid cannot be cured because the cured layer above it blocks UV.

  The test was conducted using a peristaltic pump with a servo controller. Curing was performed using two 8 watt UV LED light strips and attached to a cycle timer. Timing was based on a maximum waste flow rate of 14 ml / min and a 50-50 mixture of Object VeroBlack resin and FC705 support resin (both from Stratasys, Israel).

  Uncured resin can leak from pockets in stored waste, making the waste harmful.

  Reference is now made to FIG. 17, which shows five successive stages of waste resin accumulation in the cartridge. It can be seen that the resin accumulates in an essentially flat layer.

  FIG. 18 shows the hardened waste 210 removed from the cartridge. Edge 212 reveals evidence of stratification.

  Referring now to FIG. 19, it shows the formation of a sarcophagus 220. A sarcophagus is formed when the cure application is too high and the waste is cured before it has the opportunity to diffuse. If the amount applied is too low, a reservoir of uncured resin remains, which is buried under the cured resin and therefore cannot be cured thereafter.

  Referring now to FIG. 20, it shows what happens when the dosage is too low. It can be seen that the waste resin was cut into two and the pockets 230 were formed. The pocket contains uncured resin that leaks into the reservoir 232.

  Reference is now made to FIGS. The presence of icicle stones and stalagmites further causes shadowing and blocks UV from certain areas, generally resulting in a cure application dose that is too low for these areas. The result is a large number of uncured resin pockets. FIG. 21A shows a cross section of an area where shadowing has occurred, in which many such pockets 240 can be seen. FIG. 21B shows the uncured resin reservoir 242 appearing behind the sarcophagus, and FIG. 21C, in contrast, shows a cross-section of the area where shadowing did not occur, in which good stratification 244 was seen, There are no pockets.

  Referring now to FIG. 22, it shows the illumination pattern from illumination point 252 symbolized by a yellow circle using triangle 250. The arrangement of drip guides and LEDs so that all drip points receive direct illumination from both sides ensures that even if a shadowing feature is formed, there will be no points completely shadowed from both sides.

  More generally, a combination of a good drip guide design, UV timing matched to the flow rate, and LED / drip guide placement can prevent problems associated with shadows. The drip guide design and UV timing can prevent the formation of icicles and stalagmites, thus preventing or reducing the formation of shadows. This design can also ensure that the drip point is at least illuminated from at least two light sources, thus alleviating the problem when a shadowing feature is actually formed.

Referring now to FIG. 23, it shows an assembled view 260 of one embodiment of a waste treatment system. As in previous embodiments, the system has specific functions including:
1) Transfer the waste resin and distribute the resin evenly in the waste cartridge.
2) When waste resin is produced, it is cured.
3) After the cartridge is full, perform a final cure process to ensure that all waste ink is cured and thus chemically safe before disposing of the full cartridge.

  Waste resin is generated at two locations: a maintenance station that performs the maintenance procedure of the head and a roller. Waste from these locations is transferred to a waste curing system via a piping set consisting of tubes and fittings. The longer tube 262 gets waste from the rollers and the shorter tube 264 gets waste from the maintenance station. The piping set merges the flow of waste resin coming from the roller and maintenance station at the junction 266 between the two tubes and delivers the flow to a single inlet of the waste diverter 268. See the exploded view of FIG. This transfer is usually induced by gravity. However, in some embodiments of the invention, the transfer of waste material in the piping set may be controlled by one or more mechanical devices such as peristaltic pumps.

  From this point on, the even distribution of waste material within the cartridge container is handled by the waste diverter 268 and showerhead 270 components. With reference to FIG. 25, the waste diverter 268 divides the flow into four evenly spaced drip points 272, 274, 276, and 278. These drip points are aligned with the four inlets of the showerhead 270 and the passages to each drip point are the same length. In the illustrated embodiment, this result is achieved by using a looped channel to the closer drip points 272 and 274 as opposed to a more linear channel to the farther drip points 276 and 278. The The fact that the distance is the same helps to ensure that the hydraulic pressure is the same in all paths. Again, the paths may be arranged at the same height to ensure that there is no preferred path and that the resin flow is as uniform as possible.

  The large opening 280 cures the waste material remaining in the showerhead 270 and allows for the insertion of an LED lamp to seal the waste cartridge prior to disposal in a standard waste bin. The lamp distribution is made to ensure that any remaining material present in the showerhead 270 is cured before the cartridge is disposed of. A safety opening 282 is located over at least some of the drip points of the showerhead 270 to help evacuate waste material from the waste diverter 268 in the event of waste overflow.

  Referring now to FIG. 26A, it is a simplified view of the showerhead 270. The showerhead 270 matches the four drip points on the waste diverter 268 and divides each of the four streams into six new drip points on the cross and diagonal pattern 284 to form a total of 24 drip points. . The 24 drip points ensure even distribution of the resin in the cartridge because the drip points of the showerhead are evenly arranged in the plan view of the cartridge. Thus, the resin deposits evenly as it drops into the container portion of the waste cartridge. Since the curing LED only lights up intermittently, the waste has time to check its liquid level and merge into a relatively uniform layer during the curing cycle. Transfer through both the waste diverter 268 and the showerhead is caused by a combination of gravity and wicking. However, in some embodiments of the invention, the transfer of waste material in the waste diverter and / or showerhead may be controlled by one or more mechanical devices such as peristaltic pumps.

  FIG. 26B shows details of the cross and diagonal pattern 284. The showerhead indicates that corner rounding is used to help or prevent wicking. The resin is specially designed to be wicked within a small area of the printhead firing chamber. This helps to prime the print head and keep it primed. Of course, the positive wicking behavior from the resin also occurs outside the print head. The wicking action occurs most often at narrow corners with a small or no radius, so that sharp corners are realized where resin drainage or stagnation is desired. Thus, the shower head is provided with a sharp corner at the bottom inside the flow path intended for the resin to flow. Conversely, the outer walls of the flow path have a very large radius to prevent any wicking from the flow path.

  When an even distribution of the material is achieved, it results in a consistent layer thickness and thus excellent curing performance. In the waste curing system of this embodiment, the flow to a single inlet is divided into 24 separate streams by the waste diverter 268 and the showerhead 270 as described above. This design element described ensures that the flow is evenly divided between the 24 drip points of the showerhead 270.

  Referring again to FIG. 24, the side strip 290 holds several LED elements on one or more printed circuit assemblies (PCAs) that perform curing on the resin inside the cartridge container.

  In certain embodiments, the curing function is achieved through at least two such UV LED-carrying side strips 290 disposed on a polished sheet metal reflector 292 on both sides of the container 294. The reflector 292 can help scatter the light from the LED inside the container, thereby improving the uniformity of curing. Periodically, when waste is generated, the LED operates for a cure cycle to cure a layer of liquid waste accumulated on the container floor or the cured resin in the container.

  When the cartridge is full, a final curing step is performed before discarding the cartridge. Since liquid resin is considered a hazardous substance, it is necessary to cure the residual resin remaining in the distribution channel above the showerhead before discarding the cartridge. A third PCA with UV LEDs can be placed on the showerhead for this purpose. When the waste cartridge is full, the LED on the third substrate is activated. The operation of the third substrate hardens all the liquid resin remaining in the shower head 270. Final curing also helps to seal the top hole of the cartridge. Such sealing is desirable because some water may leach out of the cured waste resin. Once the final cure step has taken place, the drip point of the showerhead is sealed so that the cartridge can no longer be used.

  Referring now to FIGS. 27, 28, and 29, they show details of the waste diverter 268, each from three different angles. The waste inflow tube drip waste to the central location 300 where the shielding wall 302 keeps the resin away from the UV holes 304. The surface wicking channel 306 acts as a duct, splitting the resin flow in each of the four outlet directions and causing the dripping resin to start flowing in four separate directions.

  Waste drops at a central location 300 that serves as a small temporary reservoir at the entrance. The reservoir distributes the resin evenly at the inlets of all four diverter paths. A small wicking channel 306 is formed at the bottom of the reservoir. These again help to disperse the resin across the surface of the reservoir. Channels reduce flow when there is no possibility that the resin will accumulate on one side and start wicking preferentially to one or the other of the flow paths rather than all of the flow paths With the goal. When sufficient resin accumulates in the reservoir, the resin level rises and matches the starting point of the flow path. The inlet of the channel also incorporates the wicking function. Their purpose is to ensure that the resin is drawn into all four paths, again preventing the flow from preferentially flowing down one or two of the paths.

  FIG. 30 is a schematic cross-sectional view of the waste diverter 268 showing that one inlet 310 is divided into four equally spaced outlets 312, 314, 316, and 318.

  FIG. 31 is a schematic cross-sectional view showing waste diverter 268 and showerhead 270 attached together. As shown, the four outlets of the waste diverter coincide with the four inlets of the showerhead and further divide the flow into equally spaced showerhead outlets 320.

  Referring now to FIGS. 32, 33, and 34, they illustrate the nozzle structure of the showerhead 270 that prevents the nozzle from becoming clogged due to unintentional curing of the resin dripping from the nozzle. Inevitably, the bottom of the drip point in both the waste diverter and the showerhead needs to be exposed so that the droplet can fall. This makes clogging more likely when stray UV light cures the resin there. The showerhead is part of the disposable cartridge and therefore needs to be kept clogged only for the lifetime of the cartridge, not the lifetime of the product. However, since the showerhead is exposed to UV doses more frequently and than a waste diverter, protecting the drip point of the showerhead is also a challenge.

  Therefore, to prevent the resin from curing while still in contact with them and thus sealing them, the drip points in both the waste diverter and the showerhead must be protected from stray UV. This can be accomplished by incorporating a shielding wall that can be arranged to form a lampshade structure 330 around the drip nozzle 332 as described above. In the waste diverter 268, the lamp shade structure 330 can extend below the top of the showerhead 270, leaving only minimal clearance to allow cartridge insertion and removal. In some embodiments, the waste diverter 268 is intended to persist over the life of the printer, so that protection is preferably as complete as possible.

  The drip point 320 of the showerhead 270 also has a lamp shade structure 330 to minimize their exposure to UV, as seen in FIG. There are several parameters that should be traded off in determining the size of the lampshade structure 330. The first parameter is the angle from the inner wall to the tip. Experimentally, a depression angle 334 of less than 50 ° (see FIG. 33) has been found to provide sufficient protection for the LED / reflector / drip point configuration of this embodiment. The second parameter is the inner diameter. If the inner diameter is too close to the drip point, the resin may bridge between the drip point and the inner wall of the lampshade and begin to drip from the lampshade rather than the drip guide, resulting in the formation of icicle stones. unknown. Another feature that helps prevent the formation of icicles is the drop point and the root radius of the lampshade. Here, if the radius is large, wicking of the resin from the drip point to the lamp shade is prevented.

  The last trade-off parameter is height. The higher the diameter (desirable for preventing icicle stones) and the smaller the angle of depression at the tip (desired from the viewpoint of protecting the drip point), the higher the lamp shade height is required. However, the higher the lampshade height, the smaller the usable height of the cartridge. The challenge is to maximize the usable volume of the cartridge by making the lampshade diameter the smallest diameter that prevents the formation of icicles and the maximum depression angle that prevents clogging.

  Referring now to FIG. 35, it shows the formation of icicle stone 336 in the nozzle 338 which is improperly shielded. Icicle stones clog the nozzles and make the cartridge useless long before it is full.

  Referring now to FIG. 36, it is a bottom view of the shower head 270 with LED lamps 340 installed on both sides of the cartridge. This figure shows the placement of the LED lamp 340 around the drip point of the showerhead 270 that provides as uniform cure as possible.

  One of the challenges in the design of the waste curing system has been to ensure uniform UV exposure even when icicle stones / sarcophagus are formed. To meet this challenge, special attention must be paid to the mutual arrangement of the LED 340 and the drip point 320. Three drip points 320 are arranged on each of the eight inclined columns. At the same time, there are 8 LEDs in each UV LED carrying side strip 290 of this embodiment. This arrangement ensures that all drop landing areas are visible from 3-4 LEDs, so that the areas are formed of icicle stones / stone walls and blocked from one direction or the other. Even LED exposure is obtained. The arrangement configuration of FIG. 36 was effective in preventing the storage of uncured resin caused by shadows.

  Referring now to FIG. 37, which shows a virtual waste pipeline (VWP) model of a printed waste disposal process according to an embodiment of the present invention. VWP models the actual waste pipeline in the printer to calculate resin flow and UV exposure requirements and timing.

  There are several problems with UV dose control. Applying the appropriate dose to the material, timing the application when the correct amount of material arrives at the cartridge, and not under- or over-applying. The VWP model helps overcome these challenges. At a high level, VWP takes into account not only the various materials, the variable volumes associated with different types of work, and the timing differences for transferring waste to the cartridge, but also the combined effects of them. , Allowing the timing of administration to be adjusted. This virtual pipeline can be used to supplement the vast variety of conditions that products encounter in the field.

  UV dose has an effect on waste curing performance. There is a range of doses that works well for a given condition (resin type, flow rate). Therefore, the dose need not be rigorously defined. However, too much or too little UV exposure can cause problems as described above. The timing of application is also relevant. If the layer formed in the container during the curing event is too thick, the material contained in the lower part of the layer will be underapplied. On the other hand, if the curing event occurs too early, not all material may be in the container when the curing event is performed. This results in the layer thickness of the next curing cycle being too high.

  As mentioned above, excessive doses of UV light can lead to the formation of sarcophagus and cause clogging and thus a hard shadow (caused by the sarcophagus structure). Underdose of UV light can lead to a hollow containing liquid resin that cannot be cured any further. The doses required for different materials are different and an underdose for one type of resin may be an overdose for another type of resin.

  The VWP model is based on a dosage unit (DU) corresponding to the volume of the waste resin material multiplied by the curing coefficient, and the curing coefficient is directly related to the curing response of the resin material to UV energy. If the waste resin is “pure” (composed of one type of resin), a single cure coefficient is applied. On the other hand, if the waste resin is a “composite” material (including two or more resins), several curing coefficients are applied, and each curing coefficient is applied to the respective volume of each recovered resin material. . Determining the waste volume of each specific resin material is determined by the amount of resin used to print the object (knowing the number of voxels printed by each resin material) and the roller or by cleaning the print head until the waste is collected Calculations can be based on the amount of waste material removed during the event. Since the DU model is applied to various inlets along the pipeline, the time it takes for the actual waste resin from different sources to reach the cartridge can be modeled. There are generally three different waste generation events. One is that the waste material is removed by the roller, and the other two is caused by a printhead cleaning event at the maintenance station. Printing is performed using a print head and nozzles, and the rollers are moped across the surface to remove about 20%, more typically 10-30% of the material. As a result, the volume of printing material is obtained and it can be estimated how much waste material has been produced. This guess provides guidance on the amount of curing energy required.

  In some embodiments, the waste material flows slowly through the tube to the cartridge. As mentioned above, gravity is a major supply factor, so there is time between estimation and the performance of curing. Due to gravity as the main supply factor, the speed depends on the amount of waste generated at any time. The more waste that is generated, the faster the waste resin is fed into the tube. These complications mean that there is no one size that fits all application quantities to prevent under- and under-dose of hard-to-cure resins. The same is true for the timing of application. There is no single timing between cure events or after maintenance that prevents over and under cure of the material in all situations. To address these issues, the VWP model of FIG. 37 can be used.

  The dose unit is applied to the resin material and again makes it possible to estimate the expected amount in the waste cartridge. The process of cleaning the print head also results in waste and is small but predictable again.

  One or more including a small tank and / or roller near the cleaning station to (1) accumulate waste material and (2) release the accumulated waste material when a predetermined deposition threshold is reached It is possible to add more accumulators. Once the volume of waste material released by the accumulator is known, the amount of resin that reaches the cartridge and needs to be cured can be determined much more accurately and appropriate curing energy (or DU) can be applied. The accumulator can also be used to introduce waste material into the pipeline at a predetermined rate. In the event of an event that generates a large amount of waste material (for example, an event where the print head material is emptied at the cleaning station), the speed limiting function is important and can control the amount of waste material entering the curing system . This also allows for tighter control of the applied DU.

  In the VWP model, the pipeline itself can be divided into cells. The DU is added to the current total DU for that cell. All contents of a cell are moved to the next cell at a configurable interval. At the end of the pipeline 356, the contents of the last cell are added to the cartridge cell 358.

  When enough resin reaches the cartridge, a cure cycle is initiated (applying a specific number of DUs) and the resin in the cartridge cell is zero. This cycle continues throughout the printing process.

  FIG. 37 shows resin accumulation 350 from two resin waste sources 352 and 354 associated with the cleaning station as well as from the rollers. Since the resin flows through the tube 356 at a steady flow rate, the arrival time of the cartridge cell 358 depends on the length of the tube that must travel. A delay can be entered in the calculation of each event so that the timing of the curing energy can be matched to the arrival of the resin.

  During the lifetime of a patent that matures from this application, many related additive manufacturing technologies are expected to be developed, and the scope of the term “additive manufacturing” precedes all such new technologies. It is intended to be included experimentally.

  The terms “comprises, comprising, includings, including”, “having”, and their equivalents mean “including, but not limited to, including”. .

  The term “consisting of” means “including and limited to”.

  As used herein, the singular forms (“a”, “an”, and “the”) include plural references unless the context clearly indicates otherwise.

  Certain features of the invention that are described in the context of separate embodiments for clarity can also be provided in combination in a single embodiment, and the above description is as if this combination was explicitly It should be understood that it should be interpreted as described. On the contrary, the various features of the invention described in a single embodiment for the sake of brevity are provided separately or in suitable subcombinations or as preferred in other described embodiments of the invention. The above description should be construed as if these separate embodiments are explicitly described. Certain features that are described in the context of various embodiments should not be considered essential features of those embodiments, unless that embodiment is inoperable without those elements. .

  While the invention has been described in terms of specific embodiments thereof, it will be apparent to those skilled in the art that there are many alternatives, modifications, and variations. Accordingly, the present invention is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.

  All publications, patents, and patent applications cited herein are hereby incorporated in their entirety as if each individual publication, patent and patent application was specifically and individually cited. It is intended to be used. Furthermore, citation or confirmation in this application should not be considered as a confession that it can be used as prior art to the present invention. To the extent that section headings are used, they should not necessarily be construed as limiting.

Claims (20)

An additional manufacturing device that generates waste ink in the process of additional manufacturing,
A waste ink recovery device configured to recover waste ink from an additional manufacturing location;
A waste ink curing device configured to cure the waste ink after collection;
With equipment. The waste ink curing device includes:
A collection cartridge for collecting liquid waste ink;
A curing energy source for curing the waste ink;
The additive manufacturing apparatus according to claim 1, comprising:   The additive manufacturing apparatus according to claim 2, wherein the waste ink curing device further includes a switch that activates the curing energy source when the ink is evenly distributed in the cartridge.   The additive manufacturing apparatus according to claim 3, wherein the switch is configured to delay the operation of the curing energy source in anticipation of a time when the waste ink droplets dripping into the cartridge join. The waste ink recovery device includes:
A reservoir for collecting the waste ink from a roller or from a printhead maintenance operation;
A piping system for distributing the waste ink to drip points distributed evenly throughout the collection cartridge;
The additive manufacturing apparatus according to claim 1, comprising:   3. The additive manufacturing apparatus of claim 2, wherein the waste ink collection cartridge includes an array of distributed drip points for distributing the waste ink evenly throughout the waste ink collection cartridge.   The additive manufacturing apparatus according to claim 2, wherein the curing energy source is arranged to radiate energy evenly over the entire cartridge.   The additive manufacturing apparatus of claim 7, wherein the curing energy source comprises a bank of light emitting diodes.   The additive manufacturing apparatus according to claim 7, wherein the curing energy source is disposed in a length direction toward one side along the cartridge.   8. The additive manufacturing apparatus of claim 7, wherein the drip point includes a shield against curing energy from the curing energy source to prevent waste ink from being cured before dripping from the drip point.   The additive manufacturing apparatus according to claim 10, wherein the shield includes a hood surrounding each drip point.   11. The additive manufacturing equipment of claim 10, further comprising a discharge shovel that directs drip under each drip point.   The curing energy source includes three diode banks, the first diode bank is disposed longitudinally on the first side of the cartridge, and the second diode bank is disposed longitudinally on the second side of the cartridge; The third diode bank is disposed in the length direction above the exit point, and the third diode bank is configured to operate once and harden the undropped ink after the cartridge reaches the full state. The additive manufacturing apparatus according to claim 7.   14. The additive manufacturing apparatus of claim 13, wherein the cartridge includes a liquid level detector that detects a current liquid level of waste ink in the cartridge, thereby determining when the cartridge is full.   15. The additive manufacturing apparatus according to claim 14, wherein the liquid level detector includes a prism having a refractive index selected to produce total internal reflection except when surrounded by the waste ink.   8. The additive manufacturing equipment of claim 7, wherein the curing energy source includes a first diode bank and a second diode bank, each oriented at an oblique angle with respect to the floor of the cartridge.   The waste ink curing device includes a cartridge for receiving waste ink from an additive manufacturing device. The cartridge includes a distribution head, a curing source, and a container. The distribution head is distributed over the inlet tube and the cartridge. An array of drip points, each of the drip points being surrounded by a shield to protect against direct irradiation from the curing source, the curing source being a plurality of radiation disposed around the container The additive manufacturing device of claim 1, comprising a location.   18. The additive manufacturing device of claim 17, further comprising a drip guide shovel below each of the drip points and within the shield.   19. The additive manufacturing device of claim 17 or 18, further comprising a second curing source in the dispensing head for curing ink remaining in the dispensing head when the cartridge is full.   20. The additive manufacturing equipment of claim 19, wherein the second curing source comprises a bank of light emitting diodes.